Solar heating of a surface produces thermal layers in the air over the surface. Such naturally-heated air layers occur in hot-climate regions, where air is heated from below by the sun-warmed ground. In these regions, buoyancy-driven vortices (e.g., “dust devils”) occur spontaneously and move about the surface before dissipating. In some cases, vortices can exhibit core diameters of up to 50 meters at the surface and heights of up to one kilometer.